Yes, at first, a really good proposal is not acceptable to either side because it requires both sides to compromise on their demands. That's what negotiations are all about.
I do play the guitar, but I just looked up the chords to John Lennon's "Imagine," and they are too complex for me. The three most accomplished pieces I play are "California Dreaming," "Rebel, Rebel," and "Third-Rate Romance," all of which might be appropriate when presenting my proposal.